Well, Henry. We say this fighter ... has a harder punch .. than this or that fighter. But I really don't know how this can actually be known who is really the hardest puncher.
It's just spectculation is all.
Often people will say a one fighter is a harder puncher than another fighter just because the fighter may have a history of winning more fights by getting the knock out.
Henry, I see no real way to know who is really the harder puncher its just merely speculation and opinions.
But in being you mentioned this ... I'll say this that boxers don't have boxer bodies any more. If we compare heavyweights in more recent times and today with the heavyweights of yesterday in past eras we know this!
Not only do the modern heavyweights not have the physical training discipline of yesterdays heavyweights of past eras. Nor, do they generally train just exactly the same ways either.
For example, there are some fighters training with weights today, and that was unheard in boxing as it had been before. The heavyweights of today are not only not as well-conditioned athletics as boxers as they use to be. But they tend to have musclebound physiques, and they appear in much better physical condition than they really are.
I've kind of gotten off on something else now. But I would only like to just further note that that the more massive and musclebound a fighters body is the quicker his body and muscles will lose oxygen and when that happens in a fight your t-o-a-s-t! If you don't have the stamina your going to get your his butt whooped!
In part, at least this is the reason and can be much the reason that its even all the more harder as to why its hard for heavyweights today to go long rounds compared to the heavyweights in past eras. But going long rounds has always been hard for heavyweights.
Hey, its a good thing that they don't have 15 round fights any more ... for there are a lot of guys in the pros today and most especially in the heavyweights classes that would not be able to go 15 rounds today even with five air tanks on their backs.
Often I'm critical of our sport today in my posts though I really don't mean to be. Its just that I'm old enough to remember the way it was. At least I can say I know the way it was as far back as the 1960's because I was there. I boxed amatuer in those years and I saw the great pro fights of those years.
As for Rocky Marciano ... I was too young to have seen his fights. So all have to go by is what others say about him ... and by watching tapes that I have of what many would consider to be his greatest fights.